1. Field of the Invention
This invention relates to a laser shield which has particular utility in surgical applications.
2. Description of the Prior Art
High-powered lasers are now being widely used in medical therapy and surgical techniques to remove and/or repair tissues. A need exists for a laser-resistant surgical drape to protect the patient and prevent burning of tissues and other objects in the surgical field. Solid metallic shields often used to absorb or reflect laser radiation are not adaptable as a surgical drape since they are not flexible and would reflect too much of the laser radiation (a potential hazard). Wet towels are sometimes used in surgical applications for laser protection but they offer only about 0.5 seconds of protection or less (per layer) and are limited to protection from CO.sub.2 lasers. Furthermore, the use of wet materials requires the operating room staff to moisten the material and monitor the material for dryness throughout the operating procedure.
Surgical packs and drapes commercially available as "Spunguard.RTM. Surgical Packs and Gowns" from Kimberly-Clark Corporation, Roswell, Ga., are made entirely of polypropylene fibers and do not ignite when exposed to a defocused laser beam. However, these drapes do not prevent penetration by the laser beam and potential burning of patient tissue beneath the drape.
Lasersafe, Inc. Pittsburgh, Pa., has developed a series of aluminum shields for eyes and equipment. These shields are constructed with cotton gauze on the interior side and aluminum on the exterior. These products strongly reflect the laser beam creating the possibility that it may strike the patient or operating room staff. Furthermore, the gauze material used would not be suitable in a surgical drape since it is a linting material which can both cause granuloma and carry bacteria.
Aluminum tape is recognized as good protection for endotracheal tubes during otolaryngeal laser surgery. There is concern, however, that reflection of radiation from the metal may spuriously strike the patient or other operating room personnel.
U.S. Pat. No. 4,558,093 discloses a laser shield for use in surgical applications. The shield consists of densely-packed bubbles encapsulated in a matrix of silicone. The bubbles can be water bubbles and/or glass bubbles which may be filled with gas. The shields are said to be useful to terminate CO.sub.2 laser radiation.